问Silverlight 4内存泄漏与ItemsControl

EN

    public class DataSrc  :INotifyDataErrorInfo
{
    public string Name { get; set; }

    public IEnumerable GetErrors(string propertyName)
    {
        yield break;
    }

    public void InvokeEvent()
    {
        _weakLinkErrorChanged.OnEvent(this, new DataErrorsChangedEventArgs("Name"));
    }

    private WeakLinkErrorChanged<DataSrc, object> _weakLinkErrorChanged;

    public event EventHandler<DataErrorsChangedEventArgs> ErrorsChanged
    {
        add 
        { 
             _weakLinkErrorChanged=new WeakLinkErrorChanged<DataSrc, object>(this);
            _weakLinkErrorChanged.ErrorsChanged += value;
        }

        remove { _weakLinkErrorChanged.ErrorsChanged -= value; }
    }

    public bool HasErrors
    {
        get { return false; }
    }
}


internal class WeakLinkErrorChanged<TInstance, TSource> where TInstance : class
{

    private readonly WeakReference _weakInstance;

    public event EventHandler<DataErrorsChangedEventArgs> ErrorsChanged;

    public WeakLinkErrorChanged(TInstance instance)
    {
        if (instance == null)
        {
            throw new ArgumentNullException("instance");
        }

        _weakInstance = new WeakReference(instance);
    }

    public void OnEvent(TSource source, DataErrorsChangedEventArgs eventArgs)
    {
        var target = _weakInstance.Target as TInstance;

        if (target != null)
        {
            if(ErrorsChanged!=null)
                ErrorsChanged(target, eventArgs);
        }
        else
            ErrorsChanged = null;
    }
}